The New Science Of Why Women Cheat - Macken Murphy

A New EvPsych Study on Infidelity rel="noopener noreferrer" target="_blank">(00:00:00)

• The evolutionary drivers of female infidelity have been a subject of debate among evolutionary psychologists. The dominant theory, known as the Dual Mating Hypothesis, proposed that women engage in infidelity to obtain "good genes" from one partner while maintaining the parental investment of another. This hypothesis was supported by studies that found women were more likely to engage in infidelity during their ovulatory phase.
• However, subsequent research with larger samples and more robust methods challenged the Dual Mating Hypothesis. The ovulatory shift effect, which was the primary evidence for the hypothesis, was found to be less reliable. This led some researchers to propose an alternative hypothesis, the Mate Switching Hypothesis, which suggests that women engage in infidelity to find a better overall mate, rather than just seeking "good genes."
• The Mate Switching Hypothesis was tested in a study of the Himba people in Namibia, but the results were inconclusive. While some evidence for the Dual Mating Hypothesis was found, the study did not support the Mate Switching Hypothesis. This led to the development of a new study that directly compared the predictions of the Dual Mating Hypothesis and the Mate Switching Hypothesis. This study involved a large sample of individuals who had engaged in infidelity and found that women who had affairs perceived their affair partners as being more attractive and having higher overall mate value, supporting the Mate Switching Hypothesis.

How Macken Conducted the Survey rel="noopener noreferrer" target="_blank">(00:10:09)

• A survey was conducted to investigate the motivations behind infidelity, specifically focusing on the "M-switching hypothesis" and the "Dual mating hypothesis."
• The survey involved three questions: demographic information, whether the participant had ever been in a sexually exclusive relationship where they slept with someone else, and if they were interested in participating in further research.
• The survey was sent to 1,500 people, with 254 individuals completing the full study.
• The M-switching hypothesis predicts that women who have affairs seek a better mate overall, including as a co-parent.
• The Dual mating hypothesis suggests that women prioritize good genes from an affair partner and good parenting from their primary partner.
• The study found that affair partners were rated as more physically attractive than primary partners, while primary partners were rated as more parentally attractive.
• This crossover effect supports the Dual mating hypothesis, as it suggests that women prioritize different qualities in their affair and primary partners.
• The study did not find any significant differences in overall mate value or personality between affair partners and primary partners, contradicting the M-switching hypothesis.
• The study also found that men exhibited the same pattern, prioritizing physical attractiveness in affair partners and parental qualities in primary partners.
• The results suggest that the Dual mating hypothesis may be a human strategy, with both men and women prioritizing different qualities in their affair and primary partners.

Evolutionary Benefit of Men Cheating rel="noopener noreferrer" target="_blank">(00:20:31)

• Evolutionary psychology suggests that men cheat to increase their reproductive output by having more offspring. This is because men have a theoretically unlimited reproductive potential, unlike women who have a limited number of eggs.
• The study did not find support for the hypothesis that men cheat purely for quantity. While the study did not specifically test this hypothesis, it did not find evidence to support the idea that men are driven by a desire to maximize the number of partners.
• The study found no significant sex differences in the reasons people reported for cheating. Both men and women reported similar reasons, such as sexual boredom and a desire for novelty. This suggests that the reasons for cheating may be more complex than simply a desire for quantity.

Is Cheating Just Novelty Seeking? rel="noopener noreferrer" target="_blank">(00:25:36)

• The text discusses whether cheating is simply driven by novelty seeking.
• While novelty may play a role, the data suggests it's not the sole factor.
• The data shows that affair partners are often perceived as more physically attractive than main partners, even though this difference is not observed in other areas like mate value, personality, or parental attractiveness.
• This suggests that the increased physical attractiveness perception might be linked to novelty, but it's not simply a matter of positive illusions associated with novelty.
• The text acknowledges that a study comparing ratings of affair partners and main partners by independent observers would be ideal to further investigate this phenomenon, but it raises ethical concerns due to the sensitive nature of the topic.

Key Learnings From the Study rel="noopener noreferrer" target="_blank">(00:28:30)

• Relationship dissatisfaction was the most common stated motivation for infidelity in both men and women. However, women were significantly more likely to mention relationship dissatisfaction as a reason for their infidelity (65%) compared to men (30%).
• The study's methodology allowed for multiple motivations to be coded for each infidelity event. This means that a single infidelity event could be coded for both relationship dissatisfaction and other factors, such as the attractiveness of the affair partner.
• The higher rate of relationship dissatisfaction among women who commit infidelity is often interpreted as evidence for the "mate switching hypothesis." This hypothesis suggests that women are more likely to seek a new partner when they are dissatisfied with their current relationship. However, the study's authors argue that this interpretation is not necessarily accurate.
• The authors suggest that women may be more sensitive to cues of relationship dissatisfaction and more likely to express it. Additionally, they argue that infidelity is a riskier activity for women, as it is more likely to lead to relationship dissolution. This higher risk may lead women to be more attuned to their relationship satisfaction levels and more likely to engage in infidelity when they are dissatisfied.
• The authors emphasize that relationship dissatisfaction does not necessarily equate to a desire to end the relationship. Many individuals who are dissatisfied with their relationships may still want to work on them and stay together.

Can Women Separate Emotions From Sex? rel="noopener noreferrer" target="_blank">(00:35:23)

• The text discusses the idea that women may be more likely to develop emotional attachments to sexual partners in general, not just affair partners, as a potential explanation for the observation that women are more likely to fall in love with their affair partners than men.
• The text notes that in a study, love for an affair partner was not a significant motivating factor for either men or women having affairs.
• The text explores the concept of "mate switching" and how it relates to women's preferences for traits in potential partners, particularly in the context of sperm donation and embryo selection.
• The text highlights the difference between individual-level preferences for traits in offspring and societal-level concerns about eugenics.
• The text discusses a study that compared stated preferences for traits in a partner with actual romantic evaluations, finding that physical traits are more important than people report, particularly for women.
• The text concludes by emphasizing the importance of considering both stated and revealed preferences when studying mate selection.

Top 3 Motivations for Women Cheating rel="noopener noreferrer" target="_blank">(00:46:20)

• Relationship Dissatisfaction: The most common motivation for women cheating was dissatisfaction with their primary partner, specifically their partner's lack of investment in the relationship. This was cited by 22% of women.
• Revenge: The second most common motivation for women cheating was revenge, specifically for their partner's infidelity. This was cited by 15.5% of women.
• Physical Attractiveness: While not the primary motivation, 5% of women mentioned their affair partner's physical attractiveness as a factor. These women were 77% more likely to find their affair partner physically attractive than their primary partner.

Evolution of Male Parental Uncertainty rel="noopener noreferrer" target="_blank">(00:53:14)

• Male Parental Uncertainty: The text discusses the concept of male parental uncertainty, which is the concern that a man may be raising a child that is not his biological offspring. This uncertainty is a significant factor in human evolution, as it has shaped men's mating strategies and behaviors.
• Prevalence of Cuckoldry: While the text acknowledges that the prevalence of cuckoldry (raising another man's child) is relatively low in modern populations (estimated at 1-3%), it argues that this low rate is influenced by factors like social norms against infidelity and the availability of contraceptives. In populations with less access to contraceptives, rates of extra-paternal paternity can be significantly higher.
• Evolutionary Significance: The text emphasizes the evolutionary significance of male parental uncertainty, arguing that it has driven the development of men's sensitivity to paternity certainty. The existence of this sensitivity suggests that paternity uncertainty has been a recurring issue throughout human history.
• Dual Mating Hypothesis: The text explores the Dual Mating Hypothesis, which proposes that women may engage in both long-term and short-term mating strategies. This hypothesis is often met with criticism, with some arguing that it is sexist or paints women in an unfavorable light.
• Evolved Psychological Influences: The text counters these criticisms by highlighting that evolved psychological influences on men's sexual behavior are equally unfavorable, often involving deception, emotional detachment, and a desire for variety. The text emphasizes the importance of understanding these influences, regardless of how "icky" they may seem, in order to better understand human behavior.
• Feminist Perspective: The text clarifies that the primary advocates for the Dual Mating Hypothesis are often feminists and gender egalitarians, who are interested in understanding the truth about human sexuality, regardless of potential political implications.
• Agency and Choice: The text emphasizes that women are active sexual strategists with agency and choice in their sexual behavior. It criticizes the notion that women are passive or solely reactive in their sexual decisions, arguing that this perspective is patronizing and sexist.
• Strategic Choices: The text suggests that women, like men, make strategic choices regarding infidelity, driven by their own evolved psychological motivations. This perspective challenges the idea that women are solely responsible for or culpable for infidelity.

Men’s Motivations for Cheating rel="noopener noreferrer" target="_blank">(01:02:53)

• Relationship dissatisfaction is the most common reason men report for cheating, with approximately 30% of men citing this as their motivation.
• Attractiveness of the affair partner is another significant factor, with about 16% of men reporting this as a reason for cheating.
• Sexual desire is reported as a motivation for cheating by 14% of men, although the speaker suggests this may be an underreported reason due to social stigma.
• Mate switching is a motivation for cheating for some men, meaning they are seeking a new partner altogether.
• Information acquisition is a less common but still present motivation for cheating, with some individuals seeking to gain skills in seduction or to calibrate their own mate value.
• Multiple investors is a hypothesis that suggests some individuals may engage in infidelity to obtain additional resources from multiple partners, particularly in situations where resources are scarce.
• The "princess treatment" strategy is a recent phenomenon where women use manipulative tactics to secure financial support from men, potentially involving multiple partners.

Why Men & Women Get Jealous rel="noopener noreferrer" target="_blank">(01:12:03)

• Evolutionary Psychology and Jealousy: The text discusses the evolutionary psychology perspective on jealousy, specifically the "Dual Mating Hypothesis." This hypothesis suggests that men and women have different evolutionary pressures regarding infidelity, leading to different levels of concern about sexual and emotional infidelity.
• Sex Differences in Jealousy: On average, men are more concerned with sexual infidelity, while women are more concerned with emotional infidelity. This difference is explained by the potential for men to be "cuckolded" (raising children that are not their own) and women's greater investment in raising children.
• Investment Uncertainty and Paternity Uncertainty: Women have "investment uncertainty" because they are unsure if a man will continue to invest in them and their children. Men have "paternity uncertainty" because they cannot be completely sure they are the father of a child. These uncertainties drive the different levels of jealousy.
• Cuckoldry and Infanticide: The text explores the concept of "cuckoldry" and its potential evolutionary implications. It suggests that in ancestral contexts, men may have been more likely to raise children that were not their own due to high rates of infidelity and low contraception use. The text also mentions the possibility of infanticide as a factor in human evolution, similar to the behavior observed in chimpanzees.
• Political Context and Scientific Findings: The text highlights the changing political interpretations of scientific findings related to sex differences in infidelity. Findings that were once championed by feminist scholars are now often rejected by feminist groups, while being embraced by groups with more traditional views. This illustrates how scientific findings can be interpreted through different political lenses.

What Are the Predictors of Infidelity? rel="noopener noreferrer" target="_blank">(01:20:28)

• Past Infidelity: Individuals who have cheated in previous relationships are more likely to cheat again. Studies show that those who cheated in their last relationship are three times more likely to cheat in their next one.
• Extra-Pair Interest: People who exhibit a strong interest in individuals outside of their current relationship are more likely to engage in infidelity. This includes behaviors like constantly checking out other people, lingering eye contact, and engaging in extra-pair flirtation.
• Narcissism: Narcissistic individuals are more prone to infidelity.
• History of Promiscuity: Individuals with a history of casual sex and multiple partners are more likely to cheat than those with a history of monogamous relationships.
• Sociosexuality: People who are more open to casual sex and less restricted in their sexual behavior are more likely to engage in infidelity. This is often reflected in a higher "body count" or number of past sexual partners.
• Digital Secrecy: A sudden increase in digital secrecy, such as refusing to share phone access, leaving the room with their phone, or being overly protective of their phone, can be a sign of infidelity.

Signs That Someone is Actively Cheating rel="noopener noreferrer" target="_blank">(01:28:57)

• Digital Secrecy: While digital secrecy can be a sign of infidelity, it can also be attributed to other reasons. It is difficult to imagine a modern affair occurring without some level of digital secrecy.
• Active Cheating: Research on active cheating is limited due to the secretive nature of the behavior. It is difficult to study individuals actively engaging in infidelity as they are trying to conceal their actions.
• Trusting Your Gut: While it is important to be cautious, trusting your intuition to some extent is advisable if you suspect infidelity. However, it is crucial to consider your personal history and avoid overreacting based on unfounded jealousy.
• Social Media Signals: Studies have shown that certain behaviors on social media can signal commitment within relationships. These include deleting dating apps, ignoring flirtatious messages, indicating relationship status online, and unfollowing potential alternative mates.
• Attachment Anxiety: Individuals with high attachment anxiety experience heightened discomfort and jealousy when imagining their partner interacting with attractive alternatives on social media. While explicit commitment signals on social media can increase perceived partner commitment, they may not fully alleviate the insecurities associated with attachment anxiety.
• Evolutionary Roots of Social Media Signals: The act of broadcasting a relationship on social media can be seen as an evolutionary adaptation similar to the duets sung by Gibbons, a socially monogamous primate species. These duets serve to signal the pair bond and deter potential rivals.

What Counts as Cheating? rel="noopener noreferrer" target="_blank">(01:33:22)

• The definition of cheating varies greatly depending on the relationship dynamic. For example, in open relationships, sexual activity with someone other than one's partner may not be considered cheating. Conversely, in more restrictive relationships, even fantasizing about other people could be considered cheating.
• The study discussed in the text focused solely on sexual affairs, not emotional affairs.
• The speaker suggests that emotional affairs may be more geared towards mate switching, while sexual affairs may be more geared towards dual mating.
• The speaker acknowledges that the study's focus on sexual affairs may have biased the results towards the dual mating hypothesis, as emotional affairs may be more relevant to mate switching.
• The speaker notes that emotional affairs can be a safer form of infidelity, as they allow for more deniability and insulation from the potential costs of being caught.
• The speaker highlights that sexual affairs can provide valuable information about a potential mate, such as their conscientiousness, athleticism, and level of care for their partner.

Is Cheating Heritable? rel="noopener noreferrer" target="_blank">(01:38:08)

• Cheating is heritable. Studies, including twin studies, suggest that genetic factors influence a person's propensity to cheat. While the exact genes involved are complex and numerous, they likely affect various traits like risk-taking, sociosexuality, and honesty.
• The Fraternal Birth Order Effect and Sexual Orientation. Research indicates that individuals with more older brothers are more likely to be gay, both for men and women. This effect is observed in populations from Croatia and Slovakia. The evolutionary explanation for this phenomenon is unclear, and the existing hypothesis of kin selection, which suggests that men with more older brothers are more likely to become kin helpers due to a skewed sex ratio, does not fully explain the effect on women.
• The "Rich Gay Uncle" Hypothesis. This hypothesis suggests that gay individuals may have evolved to be more successful financially and invest more in their nephews and nieces. While some anecdotal evidence supports this idea, it is not widely accepted as a definitive explanation for homosexuality.
• Evolutionary Psychology and the Importance of Rigorous Testing. The speaker emphasizes the need for caution when applying evolutionary psychology to explain complex behaviors. While it can be tempting to create stories, it is crucial to rigorously test hypotheses and avoid oversimplification.

What Type of Person Gets Cheated on? rel="noopener noreferrer" target="_blank">(01:44:33)

• Research suggests that individuals who have been cheated on in a previous relationship are more likely to be cheated on in future relationships. This could be due to a lack of skill in "mate guarding," which refers to the ability to prevent infidelity.
• Another possibility is that individuals are repeatedly attracted to partners who exhibit narcissistic traits, which are known to be associated with infidelity. This suggests that individuals may be drawn to certain personality types that increase the likelihood of being cheated on.
• It is also possible that some individuals are more adept at detecting infidelity, leading to a higher perceived rate of cheating. Conversely, others may be less likely to notice infidelity due to their own trust levels or lack of suspicion.
• The text suggests that individuals who consistently experience infidelity may need to examine their own choices and preferences. This includes considering the traits they find attractive in partners and whether those traits are correlated with infidelity.
• The text emphasizes that while there may be factors contributing to repeated infidelity, it is not intended to be victim-blaming. Instead, it encourages individuals to reflect on their own choices and patterns in relationships.

Is Infidelity Natural? rel="noopener noreferrer" target="_blank">(01:49:16)

• The speaker discusses a study on female infidelity and its implications for understanding human mating strategies. The study found that while some women engage in "dual mating" (having a primary partner and an affair partner), it is not as common as initially expected.
• The speaker emphasizes that the study is just one piece of the puzzle and more research is needed. They also note that women cheat for various reasons, including seeking additional resources or revenge.
• The speaker clarifies that the study does not necessarily challenge the idea that humans are socially monogamous. They explain that many socially monogamous species, including humans, engage in extra-pair mating. The speaker cites a study on Gibbons, a socially monogamous primate, where 11-12% of sexual encounters were with partners other than the primary mate.
• The speaker addresses the potential role of ovulatory shift in infidelity, acknowledging that it is a compelling hypothesis but one that has not been consistently replicated in research. They suggest that more sophisticated study designs that consider relationship factors might be needed to validate the ovulatory shift hypothesis.
• The speaker emphasizes that the dual mating hypothesis does not require ovulatory shift. They argue that there are potential benefits to having sex outside of the fertile window, both within and outside of a primary relationship.
• The speaker concludes by highlighting the remarkable sexual stability humans exhibit across their menstrual cycles, suggesting that even if dual mating occurs, it does not necessarily contradict this stability.

Where to Find Macken rel="noopener noreferrer" target="_blank">(01:56:19)

• The speaker is excited to see Chris Williamson in Australia in a couple of months.
• The speaker has tickets to Williamson's concert in Melbourne.
• The speaker will be attending the concert and will be available to meet fans.
• The speaker's podcast is called "Species."
• The speaker has an app for couples called "Coule."
• The speaker has a course on human evolution.
• The speaker's work can be found by searching for his name on Google.